MEXICO CITY -- Mexico's biggest retailer, Wal-Mart de Mexico SAB, reported double-digit sales growth in September as emergency purchases following a major earthquake offset the impact of temporary store closures.

Walmex, as the unit of Bentonville, Ark.-based Wal-Mart Stores Inc. is known, said same-store sales in Mexico grew 10.2% last month, and total sales including stores opened in the past year rose 12%. There was also a positive calendar effect this year with one additional Saturday in September.

Overall sales including operations in Central America rose 10.3% from September 2016 to 44.2 billion Mexican pesos ($2.4 billion), and were up 8.9% for the first nine months of the year.

A 7.1-magnitude earthquake on Sept. 19 killed 369 people in Mexico City and central states. In the capital, 38 buildings collapsed and thousands were badly damaged. The earthquake led to the temporary closure of 94 Walmart stores, 55 of which reopened the next day and more than 30 two days later.

Walmex said the closures were more than offset by people rushing to buy supplies to stock up or to donate to those affected by the quake. It estimated that those purchases added about 1 percentage point to same-store sales growth in September.

The company said it donated 40 million pesos ($2.2 million) to help people affected by the earthquake, and distributed more than 300 tons of basic items, including first-aid supplies, via Mexican armed forces.